In processes of manufacturing color filters or various interconnections for liquid crystal displays, organic EL displays, plasma displays and the like, an inkjet process is being widely used.
The inkjet process is a method in which a liquid material is printed on a substrate according to a predetermined pattern and then dried, thereby forming a desired thin film. Accordingly, the inkjet process uses a smaller amount of material than other conventional processes, and thus is known as a very economical and environmentally friendly process.
A transparent coating solution has been frequently used as an overcoat material in a process of manufacturing liquid crystal displays. The overcoat process serves to cover the lower layer of a display substrate so as to maintain the height of the lower layer at a uniform level and also serves to protect the lower layer from heat or chemicals.
Furthermore, the transparent coating solution should ensure that the properties of the transparent film formed therefrom do not change during a post-treatment process, because it can undergo post-treatment after use in a specific process, as well as a final process.
Currently, in the manufacturing of liquid crystal displays, a transparent coating solution for an overcoat layer is applied to the entire area of the lower layer of a substrate to a uniform thickness by means of a spin coater or a slit coater. In recent years, the transparent coating solution has been used in a wide range of applications, for example, it is used as white ink in an RGB plus white system obtained by adding a white layer to a three color (RGB) filter system in order to increase the brightness of a device.
Accordingly, the development of a transparent coating solution applicable to an inkjet process which allows a transparent coating layer to be formed at a desired position with a small amount of ink and which enables the thickness of an overcoat layer to be changed depending on the thickness of the underlying layer is required.